1. Field of the Invention
This invention relates to a method and device for marking an object, and more specifically to a method and device for forming bar code markings on the surface of a transparent container as part of an integrated handling system.
2. Description of the Prior Art
It is well known in the art to mark objects such as glass containers by molding, inscribing, etching or otherwise altering the surface of the object.
It is also known in the art to imprint marks on the surface of an object, for instance as described in U.S. Pat. No. 4,810,867, issued to Speicher on Mar. 7, 1989. Speicher discloses a method for imprinting bar codes on an object using an imprinting device which imprints a matrix of dots on an object which is fixed to a table assembly.
Speicher's method, as is typical of dot matrix imprinting methods, is not suitable for marking brittle materials such as glass. Also, prior art methods such as those of Speicher are typically most useful for flat items which can be readily attached to a table.
In many laboratory applications, glass or plastic vials or test tubes are marked either with a conventional bar code (to allow automated reading) or with alphanumeric markings to identify the contents. Typically paper labels having printed markings are glued on to vials. This method is deficient because the labels tend to come off when exposed to liquids or chemicals so that the information on the label is lost. Also, any surplus adhesive on the label can gum-up mechanisms in automatic handling deices (i.e., robots) often used in automated laboratory machinery. When the vials are heated, the heat can destroy the glue holding the labels on, causing the labels to fall off.
In addition, the paper labels must be glued on manually, which prevents full automation of the process of handling the vial. The paper labels also undesirably prevent viewing the contents of the vial.